“Our Little Sister” has to be seen to be believed. Not because it depends on huge explosions or special effects but because it doesn’t.

A delicate, unforced meditation on the bonds of family and the joys and wonders hidden in everyday life, this film is able to move audiences without apparent effort, and that must be experienced firsthand to be appreciated and understood.

One of the favorite films at Cannes 2015, “Our Little Sister” is the latest work by master Japanese filmmaker Hirokazu Kore-eda, a writer-director-editor whose wonderfully human films include “After Life,” “Nobody Knows,” “Still Walking” and “Like Father, Like Son,” the last of which won the Cannes jury prize in 2013.

This time, working from a graphic novel by Akimi Yoshida, Kore-eda focuses on sisters and their relationship to one another, starting with three siblings in their 20s who live together in an old ramshackle family house in the charming seaside town of Kamakura south of Tokyo.

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But more than this, Kore-eda, as always, focuses on family, on how people relate to one another and the way life in all its inescapable complexity simply happens to the film’s protagonists and those they know and love.

“Our Little Sister’s” plot kicks in when the three Koda sisters receive the news that their “kind but useless” father, whom they haven’t seen or heard from in 15 years, has died.

Traveling to the funeral in a small town, they meet Suzu (Suzu Hirose, described in the press notes as “the Busiest 16-Year-Old in Japan”), the shy half sister they didn’t know they had. She’s the daughter of their father and the woman, also now dead, who broke up his marriage to their mother.

On an impulse but one shared by her siblings, oldest daughter Sachi (Haruka Ayase) invites Suzu to move to Kamakura and live with them. And this, despite warnings from the women’s acerbic great aunt that a child is not a pet, is just what happens.

It’s no surprise that Sachi was the sister who spoke up. A hard-working nurse, she is not only the oldest of the three but also the take-charge, most responsible one, a role she took on while still a teenager when the siblings’ mother took off.

Middle sister Yoshino (Masami Nagasawa), who works for a bank, is a different sort. More outgoing and fun-loving, always on the lookout for a boyfriend or a beer, she is mocked by Sachi “for indulging men and ruining them,” though simply having a good heart may be the cause of it all.

Chika (the single-named Kaho), the youngest Koda sister, is someone else yet again, a genial goofball who works in a sporting goods store and has her eye on a mountaineering co-worker who lost six toes in an attempt on Mt. Everest. Neither of her sisters quite understands her taste in men.

Suzu, the wide-eyed newcomer, is as eager to fit in with her siblings as they are for her to feel welcome. Over the course of a year’s four seasons, “Our Little Sister” slowly gets into the rhythm of their lives, both as individuals and a group, as time-sensitive tasks like the picking of plums and the making of plum wine occupy their spare time.

As shot by Takimoto Mikiya, “Our Little Sister” is visually attentive to the beauties of the changing landscape, with a marvelous bicycle ride Suzu takes through a veritable tunnel of blooming cherry blossoms being a special high point.

It is the nature of director Kore-eda’s style, which is warm and approachable without being in the least sentimental, that “Our Little Sister” deepens almost without our noticing it, effortlessly taking us inside the particular dilemmas of these intertwined lives.

One key statement in “Our Little Sister” comes by way of the sisters’ late grandmother (an everyday presence because of an in-house shrine), who believed that “every living thing takes time and effort.”

It’s a sentiment that the director, interviewed in Cannes when the film debuted, fully supports. “For the sisters to form a real family, you need a lot of time,” he said. “That expresses the essence of this film.”